This advisory expires at 12:00 midnight, January 13, 2013.
Tuckerman Ravine has Considerable, Moderate, and Low avalanche danger today. The Sluice, Lip, Center Bowl, and Chute all have Considerable avalanche danger. Natural avalanches are possible and human triggered avalanches are likely. Lobster Claw, Right Gully, and Left Gully have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. Hillman’s Highway, the Lower Snowfields and Little Headwall have Low avalanche danger. Natural and human triggered avalanches are unlikely except in isolated terrain features.
Huntington Ravine has Moderate avalanche danger. Central, Pinnacle, South have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. North, Damnation, Yale, Odell, and the Escape Hatch have Low avalanche danger. Natural and human triggered avalanches are unlikely except in isolated terrain features.
It looks and feels like spring this morning on the mountain. Summit temperatures are forecasted to be near 50F degrees (10C) today with an all-time January record of 47F (8C) hanging in the balance as southwest flow and morning sunshine collaborate to drive up temperatures. It is this warming that creates our avalanche concerns today. As the heat penetrates our snowpack, any weak interface between layers could release its grip on layers above leading to a wet slab avalanche. This type of instability is really hard to predict for many reasons, both from a weather based forecasters position as well as from the climber or skiers perspective while traveling in steeper terrain. Areas of concern are those with deep deposits of snow and especially deep deposits of snow which sit in direct sunshine. Bear in mind that tracks leading through these locations in no way guarantee stability.
A lot of melting as occurred in the last 36 hours which is creating some other situations to be wary of. Not only does free water in the snow pack distribute heat and lubricate bed surfaces, it also flows behind ice and builds in pressure and depth and occasionally bursts and sometimes only forms a deep pool of water best avoided. The typical spring melt-generated ice and rock fall reappear as potential hazards today after a long hiatus. Some areas below sunny buttresses and ice flows deserve a wide berth. Consideration of big chunks of ice and rock serving as triggers on warming, weakening slabs is justified.
Several areas in Huntington were dropped to Low danger today from Moderate yesterday. This is due to the amount of melting that took place and the overall quantity of snow in the gullies. Regardless of the rating, be head’s up around any larger snowfields sitting in steep terrain.
Safe travel in avalanche terrain requires training and experience. This advisory is just one tool to help you make your own decisions in avalanche terrain. You control your own risk by choosing where, when, and how you travel.
Anticipate a changing avalanche danger when actual weather differs from the higher summits forecast.
For more information contact the Forest Service Snow Rangers, the AMC at the Pinkham Notch Visitor Center, or the caretakers at Hermit Lake Shelters or the Harvard Cabin.
Posted 8:40am, January 13, 2013. A new advisory will be issued tomorrow.
Frank Carus, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856